SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '19e9b0d1dbd088d072aec169f67fd173f27883cacea5302815293a74b3222c15' 
  AND token = 'qFs5h6pBYGYUN9w6zY+TSG29eFwARMlyEHCS6jK3e9A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}